Exhibit 1

0530-EX-ST-2000 Text Documents

COMSAT Corporation/COMSAT Mobile Communications

2000-12-05ELS_43220

                                                              FCC Form 442 Exhibit 1: CMC
                                                                                 Page 1/3




                                      EXHIBIT 1

                           EQUIPMENT DESCRIPTION


PROGRAM DESCRIPTION

Comsat Mobile Communications (CMC) will be operating one fixed Satcom pallet
equipped with Honeywell Electronics Avionics at their INMARSAT ground earth station
at Santa Paula, CA. The equipment will be operated for the purpose of,

a) Test and demonstrate operation of an INMARSAT aircraft earth station (AES) with
   terrestrial public switched telephone and data systems (PSTN and PSDN) interfaces
   for voice/data/fax applications.

b) Provide capability to monitor vendor changes, training capability for the
   commissioning and Maintenance Terminal (CMT), monitoring of Land Earth Station
   (LES}/AES interface and confirm AES preference programming specifications.

The equipment shall operate in the Marine and Aeronautical Mobile Satellite band of
frequencies. Demonstration of the operational capability of this equipment requires
transmitting. No "FOR HIRE" communications are to be provided during any use of this
equipment.

DIGITAL VOICE AND DATA

The equipment shall transmit on channel of digital voice or high speed data using 21
Kb/sec (10.5) A—QPSK modulation. The system shall use a high gain stationary helix test
antenna. In addition, low speed data will be transmitted using an A—BPSK modulation.
All modulation complies with aviation standards. Ground communication services shall be
provided by CMC and other INMARSAT land earth station operators (LESOs) as
required.

OPERATING DETAILS

The bands comprising 1626.5 to 1660.5 MHz will be used. Specific frequencies and
operating schedules will be coordinated with Inmarsat, in cooperation with CMC and
other INMARSAT LESOs.

RF Power Qutput

The maximum RF power output of the equipment will be 60 Watts per carrier (17.8 dBW
peak).


                                                                  FCC Form 442 Exhibit 1: CMC
                                                                                       Page 2/3


Antenna Gain

A high gain helix antenna shall be used to provide a gain of 12 dBic and half power beam
width of 28 degrees.

EIRP

The maximum equivalent isotropic radiated power (EIRP) shall be 27.6 dBW (peak) (17.8
+9.8).
Emission Types

                                                                      Rate 1/2
       Emission        Modulation             Symbol               Convolutionally
         Type            Type                  Rate                 Encoded Rate

       $40HGID         A—BPSK                 600 baud             (600 b/sec)
       1K68GID         A—BPSK                 1200 baud            (1200 b/sec)
       3K36GID         A—BPSK                 2400 baud            (2400 b/sec)
       4K80GID         A—QPSK                 2400 baud            (4800 b/sec)
       6K72GIW          A—QPSK                4.2 kbaud            (8400 b/sec)
       10KS5G1ID       A—QPSK                 5.25 kbaud           (10.5 kb/sec)
       21KOGIW         A—QPSK                 10.5 kbaud           (21.0 kb/sec)


Modulation Methods

Type                 Description

A—QPSK               Aviation Quadrature Phase Shift Keying uses a
                     specific form of Offset QPSK where the modulation filtering is
                     optimized for satellite communications with aviation applications
                     (Reference: "Quaternary Transmission Over Satellite Channels with
                     Cascaded Non—Linear Elements and Adjacent Channel Interference" by
                     Russel Fang in IEEE Transactions on Communications, May 198]1,
                     Vol. COM—29, No. 5, pp. 567—581.)

A—BPSK               Aviation Binary Phase Shift Keying uses a specific form of differentially
                     encoded BPSK where in—phase and quadrature channels are used to
                     transmit alternate symbols. (Referenced: "Differential Detection With
                     Intersymbol Interference and Frequency Uncertainty" by J.H. Wintore
                     in IEEE Transactions on Communications, January 1984, Vol. Comm—
                   _ 32, No. 1, pp. 25—33.)


                                                                    FCC Form 442 Exhibit 1: CMC
                                                                                        Page 3/3

NECESSARY BANDWIDTH

Radiated bandwidth from the equipment is controlled by the use of raised cosine filters in the
transmitter. The A—QPSK are signals subjected to either a 60% or 100% raised cosine filter.
A 40% raised cosine filter is used for the A—BPSK signals.

The associated necessary bandwidth calculation is:

   BW=1/T (1+r)

   Where 1/T is the symbol transmission rate in symbols per second and r is the rolloff factor.

Symbol Rate       Modulation      Rolloff      Bandwidth
   (Baud)        _ Type             (1)           (BW)
    600          A—BPSK             0.4        0.840 KHz
   1200          A—BPSK             0.4        1.680 KHz
   2400          A—BPSK             0.4        3.300 KHz
   2400          A—QPSK             1.0        4.800 KHz
   4200          A—QPSK             0.6        6.720 KHz
   5250          A—QPSK             1.0        10.5 KHz
    10. 5k       A—QPSK             1.0        21.00 KHz



Document Created: 2000-12-05 10:11:23
Document Modified: 2000-12-05 10:11:23

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